Centrifugal type compressor



Manh ZZ i945. M G, RB|N5QN 2,372,518

CENTRIFUGAL TYPE COMPRES SOR Filed May 2 3, 1944 Invetor: Manuel @Robinson H Attorney.

Patented Mar. 2 7,

UNITED sTATEsA PATENT o rrica Manuel G. Robinson, Swampscott, Mass., assignor to General Electric Company, a corporation of New York Appucencn May 23, 1944, serial No. saaszo 2 blume. (ci. 23o-114) -The present invention relates to centrifugal type compressors having a variable vane vdiffuser l for converting'a part of the velocity energy of a medium impelled by the impeller into pressure energy and for varying the diiuser action upon changes in ow through the compressor. A

The object of my invention is to provide an improved construction and arrangement of compressors with 'variable vane diiusers.

- a diffuser vane ci Fis. 1.-

"The arrangement comprises a compressor casing having two halves i and 2 with flanges securely lioined together by a plurality of circumferentially Vspaced bolts 3. The casing half 2 has a number of circumferentially spaced ears 4 for attaching the compressor to a suitable support, not shown. The two casing halves have inner portions forming an impelier chamber for accommodating en impeller d secured to a shaft d rotatably supported on a Vbearing l. Outer portions of the casing halves form a scroll 8 with.

a enged discharge end t. N"I'he casing half l has a central opening or inlet l for air or like medium to be' compressed. -Fluicl impelled by the impeller is passed through a diffuser into the scroll 8.

The .diffuser has two axially spaced walls or rings Il and I2 with a plurality of circumfer- -entially spaced vanes I3 located between the walls and forming diii'user passages therewith for conducting'medium discharged from the im- 'peller to the scroll. According to my invention,

means are provided to. vary the diiuser passages. To this end each diffuser vane has a movable portion'with 9, wedge-shaped bulge. Means are provided for moving such portions into and out oi' the diiuser passages; In the present example each 4diduser has anl inner stationary part H and an outer stationary part l5 secured to or integrally formed with the diffuser wall Il. Be-

,tween the parts Ii and I5 is an inter-mediate movable partv I6 of an axial width about twice that of the inner and outer portions Il and I5. One portion of the intermediate part has a Wedge-shaped bulge I'l (Fig. 4) which upon inwall I2.

sertioninto the diffuser passages reduces considerably the cross-sectional area of the passages. Each intermediate part I 6 has another portion I8 (Fig. 4) of about the same thicknesses the inner and outer parts and upon insertion between the diffuser walls formsga smooth continuation of the inner and outer parts I4, I5 associated. therewith. The flow area formed by the diffuser passages may be gradually decreased by the insertion and withdrawal of the portions I1, the minimum flow areas being attained when the portions Il are fully inserted and the maximum flow area being attained when the portions I'I are completely removed from the passages.

The mechanism for positioning the intermediate vane parts I6 comprises an internal ring gear lil located in an annular ring chamber 2liv formed' between the casing half I andthe diffuser The ring gear i9 has an outer cylindrical surface bearing on a -cylindrical wall 2l,

'- Fig. 3, of the casing half i. The axial movement of the ring gear i9 is limited by the pro vision of a ring or plate 22 axially spaced from and integrally `formed with the diffuser wall l2. The ring gear i9 may be'rotated in either direction by means of avpinion ZSs'ecured toa shaft 24 which is rotatably supported on the vcasing and the plate 22. The shaft 2t is driven "ironi a drive shaft 25 through beveled gears 26.

Each intermediate or movable vane part I6 1s vprovided with a threaded rod 2l loosely prof jecting through an axial bore 28 in the casing half I and having screw engagement with a pinion 29 whereby rotation of the latter causes axial movement of the intermediate vane part ions 29. l The wall 22, as pointed out before, is integrally formed with thedifiuser wall I2. The two walls are connected by yan annular cylindrical flange 30 between the inner ends of the wall I2 and the plate 22. In addition the walll2 and the plate" 22 are connected by aplurality of circumferentially vspaced curved walls.3I. These walls 3l togetherwith the walls l2, 22 and the flange 3l) form rircumferentially spaced chambers 32. The

chambers 32 (Fig. l) are shaped to form a slidis completely disposed between the diuser walls u, l2 (Fina.)

The wall II of the diffuser has an, inner portion seated in an annular recess of the casing casing half I by the bolts 3.

Having described the method of operation of my invention, together with the apparatus which I now believe to be the best embodiment thereof, I desire to have it understood that the apparatus described is only illustrative and that 'the invention may be carried out by other means.

What I claim as' new and desire to secure by Letters Patent ofthe United States is:

1. A variable vane diffuser comprising twol axially spaced ring walls, and a plurality of cir- During assembly the After assembly of the impeller. in the casing half 2 the latter is secured to the' cumfcrentially spaced vanes forming diffuser A passages between said walls, each vane having inner and outer stationary parts supported on one of the walls and an intermediate part slidably projecting through aligned openings' in the walls, said intermediate part having an end portion with outer surfaces forming smooth continuations of the corresponding surfaces of the other -vane parts when disposed between said walls and another end portion which is wedgeshaped in section and forms a minimum area of ow between the vanes when disposed between said walls.

2. A variable vane diiuser comprising two axially spaced ring walls, a plurality of circumferentially spaced vanes forming diffuser passages between said walls, each vane having inner and outer parts secured to one of the walls and an intermediate Dart projecting slidably through aligned openings in the walls, said intermediate part having an end portion with outer surfaces* which is Wedge-shaped in section gradually to vary the area of flow between the vanes upon insertion between said walls, and means for simultaneously moving the intermediate parts.

2 MANUEL G. ROBINSON. 

